/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.matching;


/** Keeps track of broker destinations and profile counts per each of these
    destinations.
    @author Shrideep Pallickara
    $Date$
*/

public class ProfileCounts {
  private int destinations;
  private int[] countsPerDestination;
  private String moduleName = "ProfileCounts: ";
  private boolean ProfileCounts_Debug = false;

  public ProfileCounts() {
    countsPerDestination = new int[32]; /** limit on sub-units within a unit
					    is 32 e.g. nodes per cluster */
    for (int i=0; i < countsPerDestination.length; i++) {
      countsPerDestination[i] =0;
    }
  }

  public int getDestinations() {
    return destinations;
  }

  /** Increase the count associated with the destination. If this destination
      does not appear in the set of destinations, add it to the destination
      set and set up the destination count to 1. */
  public void incrementCountForDestination(int destination) {
    destinations = destinations | destination;
    /** position helps us retrive the location of "destination"'s entry */
    int position = determinePositionOf1Bit(destination) - 1;
    countsPerDestination[position]++;

    if (ProfileCounts_Debug) 
      System.out.println(moduleName + "Count for destination [" + destination 
			 + "]=" + countsPerDestination[position]);
  }

  /** Decrease the count associated with the destination. If the count for a  
      destination is reduced to zero as a result of this operation, remove
      the destination from the list of valid destinations for the event. If the
      destination is now reduced to zero, return <i>true</i> indicating that
      the profile be removed since the destinations associated with it has now
      reduced to zero */
  public boolean decrementCountForDestination(int destination) {
    /** position helps us retrive the location of "destination"'s entry */
    int position = determinePositionOf1Bit(destination) - 1;
    if (countsPerDestination[position] == 0) {
      System.out.println(moduleName + "Error here!!. Count for destination [" 
			 + destination + "]=" + countsPerDestination[position] 
			 + " and trying  to decrement it\n");
      /** The code should not be entering here in the first place */
      destinations = destinations ^ destination;
      if (destinations == 0)
	return true;
      
      return false;
      
    }

    countsPerDestination[position]--;
    
    if (ProfileCounts_Debug) 
      System.out.println(moduleName + "Count for destination [" + 
			 destination + "]=" + countsPerDestination[position]);

    if (countsPerDestination[position] == 0) {
      destinations = destinations ^ destination;
      if (destinations == 0)
	return true;
    }

    return false; /* do not delete entry */
  }

  /** Determines the position of "1" in the byte representation of the
      destintion. This method expects only a single "1" bit in a given
      binary representation. */
  public int determinePositionOf1Bit(int destination) {
    int tracker = 1;
    
    while ( (destination&1) == 0 ) {
      tracker++;
      /** Shift bytes to the right by 1 */
      destination = destination >> 1;
    }/*end while*/
    return tracker;
  }

  public static void main(String[] args) {
    ProfileCounts counts = new ProfileCounts();
    int test = 32;
    for (int i=0; i < 10; i++)
      counts.incrementCountForDestination(test);

    for (int i=0; i < 10; i++) {
      if (counts.decrementCountForDestination(test)) {
	System.out.println("Ready to eliminate entry in the " + i +
			   "th iteration");
      }
    }
  }

}
